List of top Physics Questions

8000 identical water drops combine together, to form a big drop. Then the ratio of the final surface energy to the initial surface energy of all the drops together is.
If plane surface of a piano convex lens is silvered, then it will behave as a
The number of $\alpha$-particles and $\beta$-particles respectively emitted in the reaction $ {_{88}A^{196} -> _{78}B^{164}}$
Longitudinal wave can travel in
A closed iron ring is held horizontally and a bar magnet is dropped through the ring with its length along the axis of the ring. The acceleration of the falling magnet is
Real gas behaves as an ideal gas, under which of the following conditions ?
A projectile is projected with speed $49\,ms^{-1}$ at an angle of $30^{\circ}$ with horizontal. The time taken by the projectile to reach the highest point is
The electrical conductivity of a semiconductor increases when electromagnetic radiation of wave length shorter than $2480\, nm$ is incident on it. The band gap (in $eV$) for semiconductor is
The potential difference across the collector of a transistor, used in common emitter mode is $1.5\, V$, with the collector resistance of $3\, k\Omega$, the emitter current is $[\beta = 50]$
A horizontal disk is rotating with angular velocity $\omega $ about a vertical axis passing through its centre. A ball is placed at the centre of groove and pushed slightly. The velocity of the ball when it comes out of the groove-
A car is moving with speed $20 \, \, \text{m s}^{- 1}$ on a circular path of radius $100 \, \, \text{m}$ . Its speed is increasing at a rate of $3 \, \text{m s}^{- 2}$ . The magnitude of the acceleration of the car at that moment is
The normal reaction on a body placed in a lift moving up with constant acceleration $2 \, m \, s^{- 1}$ is $120 \, N$ . Mass of the body is (Take $g=10 \, m \, s^{- 2}$ )
A block of mass $M$ is resting on a smooth horizontal plane. One end of a uniform rope of mass $\frac{M}{4}$ is fixed to the block, which pulled it in the horizontal direction by applying a force $F$ at the other ends. The tension in the middle of the rope is
For the arrangement in the figure, the particle $M_{1}$ attached to one end of a string which moves on a horizontal table in a circle of radius $=\frac{l}{2}$ (where $l$ is the length of the string) with the constant angular speed $\omega $ . The other end of the string attached to mass $M_{2}$ which rests on a vertical rod. When the rod collapse, the acceleration of mass $M_{2}$ at that instant
$\,^{221}_{87}$Ra undergoes radiorctive decay with a half life of 4 days. The probability that a Ra nucleus will disintegrate in 8 days is
$175$ calorie of heat is required to raise the temperature of $5$ mole of an ideal gas at constant pressure from $30^\circ\,C$ to $35^\circ\,C$. The amount of heat required to raise temperature of same gas from $30^\circ\,C$ to $35^\circ\,C$ constant volume will be
A resistor, capacitor and an inductor are connected in series and are in resonance. What is the phase difference between the supplied voltage and current ?
Capacitance of a spherical conductor of radius $R$ is proportional to
A person suffering from myopia should use a
What is the relationship between electric field intensity $E$, current density $J$ and specific resistance $\rho$ ?
When a pentavalent impurity is added in Ge crystal then, what type of semiconductor is obtained ?
If two waves of same amplitude A each produce Maximum Marks 600 a resultant wave of amplitude equal to one of its wave, then the phase difference between them will be
At what temperature the root mean square velocity of a gas is twice of its root mean velocity at $27^{\circ} C $?
In a triode, $\mu, g_{m}$ and $r_{p}$ are related as
$120\, AC$ voltage is applied to $10$ ohm resistance. The peak voltage across the resistor is